Technical Summary
The Sensor Measurement Lists (SenML) media type and data model can
be used to send collections of resources, such as batches of sensor
data or configuration parameters. The existing media types
(defined in RFC 8428) are useful for the traditional operations
GET, PUT, POST. The CoAP iPATCH, PATCH, and FETCH methods enable
accessing and updating parts of a resource or multiple resources
with one request. For using these methods to access and operate on
resources represented with the SenML data model, the present
document defines variants of the SenML media types, for JSON and
CBOR representations only.
Working Group Summary
Most of the discussion in the WG (up to and including the last
call) centered around whether the existing media types should be
shoe-horned into use with the new methods or new media types were
needed. In the end, having a simple way to apply a slight variant
won out over having a more complex way to apply something that is
nominally, but not really SenML. Christian Amsüss was kind enough
to summarize his view of the result of the discussion into a Wiki
page:
https://github.com/core-wg/wiki/wiki/On-media-types-for-FETCH-and-(i)PATCH
which will be useful in avoiding revisiting the issues when they
inevitably come up for the next media type.
Document Quality
Implementations of this media type will often be done in the context
of the OMA LWM2M specification, which is set to pick up the new media
types in future versions (1.1.1 hints: "The media types,
application/senml-etch+json and application/senml-etch+cbor, will
remove the requirement for context aware parsing."). None of the
implementations this shepherd is aware of is public yet: one existing
implementation, and one implementation that is in the product plan of
a vendor.
A media type review has been requested 2019-07-12 in
<https://mailarchive.ietf.org/arch/msg/media-types/UYGLx96gkwArLtwawiiNDBcxzTU>
Personnel
Who is the Document Shepherd? Who is the Responsible Area
Director?
Shepherd: Carsten Bormann <cabo@tzi.org> (CoRE Co-chair)
Responsible AD: Alexey Melnikov
RFC Editor Note
RFC Editor Note
For fragment identifier in 2 media types registration please include the section number 4 when referencing RFC AAAA.